Ernesto disorganized; more fires, extreme heat for Oklahoma

A disorganized Tropical Storm Ernesto continues to speed westward at 23 mph across the Caribbean. Ernesto has brought sporadic heavy rains to Jamaica today, and Kingston has picked up 0.51" of rain as of noon, and recorded top sustained winds of 22 mph. Ernesto looks very unhealthy on visible satellite loops, with its low-level circulation center a naked swirl exposed to view with almost no heavy thunderstorm activity near the center. However, the storm does have some rather far-flung spiral bands, and these bands are bringing occasional heavy downpours to Haiti, western Cuba, Jamaica, and the southwest Dominican Republic. This morning's flight by the Hurricane Hunters found that Ernesto had a very high central pressure of 1006 mb and top winds near 50 mph. The latest wind shear analysis from the SHIPS model shows moderate shear of 10 - 15 knots affecting the storm, but there must be some wind shear the satellites are not able to detect affecting Ernesto, given its disorganized appearance. Water vapor satellite loops show a large area of dry air to the west, and this dry air is also interfering with Ernesto's organization.

Figure 1. Visible satellite image with 375 meter resolution taken of Ernesto by the new Suomi NPP satellite at 1:39 pm EDT August 4, 2012. At the time, Ernesto had a flare-up of intense thunderstorms, and had top winds of 60 mph. Image credit: University of Wisconsin Madison CIMSS.

Forecast for ErnestoErnesto's rapid forward speed of 23 mph has been part of the reason for its lack of intensification, but the storm is expected to slow down Monday and Tuesday in response to a trough of low pressure passing to the north. This slowing, in combination with low wind shear, a moister environment, and increasing heat energy in the ocean, may allow Ernesto to strengthen some before making landfall in Belize or Mexico's Yucatan Peninsula on Tuesday night. However, the storm will be passing very close to the north coast of Honduras, putting a portion of its circulation over land and limiting intensification potential. It is unlikely Ernesto will become a hurricane in the Caribbean; NHC is giving just a 19% chance that this will occur. The main threat from Ernesto will be heavy rains over Honduras, Belize, Mexico, and Jamaica. The track forecast for Ernesto has become a bit easier, since the storm's current disorganization and more southerly path make will make it more difficult for the storm to make a northwesterly turn into the Gulf of Mexico like the UKMET and GFDL models are predicting. A stronger Ernesto would have been more likely to turn northwest under the influence of a trough of low pressure passing to the north. If Ernesto survives its crossing of the Yucatan Peninsula, the potential exists for it to re-strengthen over the Bay of Campeche, and make a second landfall on Mexico's coast on Friday, between Tampico and Veracruz. It's pretty unlikely that Ernesto will hit the U.S.-- though Brownsville, Texas could see some rain from Ernesto's outer spiral bands on Friday, if the storm survives that long.

Figure 2. Morning satellite image of Ernesto, showing the exposed low-level center--a swirl due south of Jamaica--and only very limited heavy thunderstorm activity surrounding the center.

Tropical Storm Florence Tropical Storm Florence continues to plow westward at 14 mph over the Eastern Atlantic, and is not a threat to any land areas for next five days. The SHIPS model is predicting a moderate 5 - 15 knots of wind shear for Florence Sunday and Monday, but the shear will increase to the high range as Florence encounters an upper-level trough of low pressure on Tuesday. The latest Saharan Air Layer Analysis shows that a large area of dry air lies to the north and west of Florence, and this dry air will likely cause problems for the storm. Ocean temperature are near 26 - 26.5°C, which is right at the threshold for where a tropical storm can typically exist. It is possible that Florence could pose a threat to Bermuda next weekend, if the storm survives that long. Both the GFS and ECMWF models dissipate Florence before then.

Historic heat wave in OklahomaA second day of destructive fires affected Oklahoma on Saturday, thanks to extreme heat and drought, low humidities, and strong winds in advance of an approaching cold front. At 3 pm CDT Saturday, Oklahoma City had a temperature of 107°, a humidity of 19%, and winds of 16 mph gusting to 22 mph. The Oklahoma fires have destroyed at least 125 homes. The high temperature in Oklahoma City on Saturday reached 109°, the 12th warmest temperature recorded in the city since records began in 1891. Friday's high of 113° tied for the warmest temperature in city history.

The only comparable Oklahoma heat wave: August 1936The only heat wave in Oklahoma history that compares to the August 2012 heat wave occurred during the great Dust Bowl summer of 1936, the hottest summer in U.S. history. Oklahoma City experienced three days at 110° that summer, and a record streak of 22 straight days with a temperature of 100° or hotter. Those numbers are comparable to 2012's: three days at 110° or hotter, and a string of 18 consecutive days (so far) with temperatures of 100° or hotter. The weak cold front that passed though Oklahoma Saturday will bring temperatures about 10° cooler over the next few days, but high temperatures are still expected to approach 100° in Oklahoma City Sunday through Tuesday. It's worth noting that Oklahoma City has experienced only 11 days since 1890 with a high of 110° or greater. Three of those days were in 2011, three in 2012, and three in the great Dust Bowl summer of 1936.

Figure 4. Most of Oklahoma has experienced nine consecutive days with highs of 100° or more, and many regions, including Oklahoma City, have had a streak of eighteen such days. Image credit: Oklahoma Mesonet.

Severe thunderstorm complex forces evacuation of Lollapalooza A organized complex of severe thunderstorms developed over Eastern Iowa and Northern Illinois late Saturday afternoon, forming a dangerous bow echo that swept through Chicago, forcing the evacuation of the Lollapalooza music festival. NOAA's Storm Prediction Center (SPC) logged over 150 reports of wind damage from the storm, with five of the thunderstorms containing winds in excess of hurricane force (74 mph.) And just yesterday, my daughter was bemoaning her misfortune at not being able to get tickets to the show! The thunderstorm complex traveled about 300 miles from Eastern Iowa to Ohio, generating winds gust in excess of 58 mph along most of its path, meeting the definition of a derecho.

Figure 5. Radar image of the severe thunderstorm complex that spawned a dangerous bow echo over Chicago, which forced the evacuation of the Lollapalooza music festival.

Bingo. Cold water from the Humboldt Current and the current that comes up South America from Antarctica. East of 130W is pretty unfavorable climatologically during the southern hemisphere cyclone season.

November-April average SSTs:

Thanks I imagine the same was for the central south pacific I really appreciate the work you do hope one day I can be good as you.

While we are all waiting for the next recon info, I want to introduce myself and ask for some info. I am Kate, long-time lurker in Vermont (and really appreciated all the info here in the run-up to Irene last year).

Can you all point me to some good sites for learning meteorology basics, beyond the limited FAQ links above? I have learned loads just lurking here over the years, but would love to know more about stuff like the physics of why stronger storms tend to veer poleward, etc, that get talked about here.

And one quick question: What is ACE?

Thank you all!

Some of these modules should be helpful, you do need to sign up, it is free.

Applaud your position. Hey, go for it! We all have opinions. ;) I'm an old novice, still learning too.

Three things have held Ernesto's development back: 1. Dry air, 2. Proximity to SAmerica; and mostly, 3. Forward speed. He's still battling two of those features though dry air is diminishing and forward speed has slightly slowed.

The forward speed has to come way down still or the storm must really strengthen for it to feel the weakness, turn and/or even feel the natural poleward tug. None of that is currently happening and he is quickly running out of liquid real estate. If something doesn't change soon, he'll come ashore in cAmerica moderate TS or weak Cat 1 at best; and that will be it for him. However, there's a pile of energy down there still, multiple vortices - something else may even spin up. Never know! ;) Keep watching! :)

Yes, he has "looked" better. However, reality said that he never really had much of a southern side to his circulation. That is currently changing. For it to continue, though, these thunderstorms need to continue blowing up.

Quoting allancalderini:Hey Levi I know this is an ignorant question but I ask Washi today but because she doesn`t follow the south pacific tropical cyclones she couldn`t answer me. my question is why tropical cyclones can form in the southwestern pacific ocean the one where the islands of Oceania and Australia are and in the southeastern can`t the one near Chile?is because of cold water?

Bingo. Cold water from the Humboldt Current and the current that comes up South America from Antarctica. East of 130W is pretty unfavorable climatologically during the southern hemisphere cyclone season.

All I can say is Ernesto has generally had a better satellite presentation than the energy actually found by the HH's. I'll wait for the next run by the HH's before I start getting excited about any change in what he looks like on satellite. He's fooled us too many times over the past four days.

Wow, whoever maintains the NASA satellite page and the RAMSDIS satellite page is asleep at the wheel. NASA satellites haven't worked for at least 3 days. Now, Ernesto's floater on RAMSDIS page is still in the Eastern Caribbean. Seems like they always work until there is something to watch.

Our thoughts go out to those in the fires:-"Historic heat wave in Oklahoma,"

Over in the Canary Islands. Massive fires are destroying a natural park know as a "patromonia de humanidad" in La Palma, Canary Islands. They dont know how to put it out, as its burning on vertical cliffs, help in the form of specialised aircraft are being drafted in! Hundreds of homes have been evacuated and many roads closed. This heat is weird stuff! Hot as hell in the day and cold at night, due to very little humidity, we get 40/C in the Day and 18/C at night. Everything's as dry as a bone and its like living in a tinder box, one spark and the local vegetation is history!

ernie is lookin like he wants to get things going. even the sat pic above in dr. masters blog showed alot of circular symmetry to him even though he didnt have any towers in the left quads....that being said the fact that he chewed up that much dry air in front of him is impressive and the stage is set for something we haven't seen in quite awhile.

i expect the trade winds push to end now that the high pressure/dry air pocket in front is now about to completely fold. instead of a push they will just wrap in, ernie will slow up, stack quick, could r.i., and may take a northerly track near the straits.....if he is strong enough and hangs over the water once he hits the 89-90 degree water in the GOM things could change even faster....way faster.....his r.i. could become scary to say the least.....

Pretty gutsy forecast. Have a look at the Gulf SST's at http://www.maineharbors.com/weather/seatemp4.htm. Except for the finger of very warm water in the Yucatan Channel, the rest of the Gulf, except for near shore waters, is nowhere near 88-90 degrees.

Quoting Doppler22:The shield is protecting against Major Hurricanes... Irene was a hurricane yes... Debby was a TS yes... But no Major Hurricanes in a while... Thats the so called shield which im hoping still holds but time may have run out... idk none of us do

The National Hurricane center is on FIU's campus (Florida Int'l University). Just off the Turnpike between the 8 street (US41) and 24 street (Coral Way). That would be considered southwestern Miami dade cty.

Recon will shortly find out whether westerly winds have redeveloped on the southern side of the center. The center is at least a defined swirl that is growing tighter now due to the new thunderstorms in proximity to it. It's on the verge of regaining a legitimate circulation.

Hey Levi I know this is an ignorant question but I ask Washi today but because she doesn`t follow the south pacific tropical cyclones she couldn`t answer me. my question is why tropical cyclones can form in the southwestern pacific ocean the one where the islands of Oceania and Australia are and in the southeastern can`t the one near Chile?is because of cold water?

Indeed. The 5 pm model ensemble seems to have shifted really far to south and now wants to take Ernesto into Belize, then into Guatemala. If this occurs, Ernesto is a dead duck. The current five day forecast track is completely disconnected from the models. Since I've thought this was Belize storm from the begining, I'm sticking with the ensemble. :)

Applaud your position. Hey, go for it! We all have opinions. ;) I'm an old novice, still learning too.

Three things have held Ernesto's development back: 1. Dry air, 2. Proximity to SAmerica; and mostly, 3. Forward speed. He's still battling two of those features though dry air is diminishing and forward speed has slightly slowed.

The forward speed has to come way down still or the storm must really strengthen for it to feel the weakness, turn and/or even feel the natural poleward tug. None of that is currently happening and he is quickly running out of liquid real estate. If something doesn't change soon, he'll come ashore in cAmerica moderate TS or weak Cat 1 at best; and that will be it for him. However, there's a pile of energy down there still, multiple vortices - something else may even spin up. Never know! ;) Keep watching! :)

Quoting TomTaylor:Agreed, although that's pretty much true every year, except for the 20N part. Usually it's more like 15N. Should be further north though with the ENSO conditions and the cool SST anomalies over the tropical Atlantic up to about 5N (almost up to 10N right off Africa).

Watch this loop. Look at the open area south of the convection around 12N. You can see the low clouds were basically stationary at that point. In the last few frames, they started moving to the east at a good clip. Ernesto could finally be fixing that southern part of his circulation.